This is arguably my favorite image of Captain America as rendered by Jack Kirby and Syd Shores.
That image became the art for this bust-out cover of the Star-Spangled Avengers Silver Age run.
The bust-out cover artwork (or possibly a splash page) above by Don Heck was for a proposed comic featuring the Liberty Legion. The book never came off. I assume the material intended for this comic was what showed up in Marvel Premiere.
Another bust-out cover by Jack Kirby it turns out.